Magnetic core for armatures



(No Model.)

T. H. HICKS. MAGNBTIG GORE FOR ARMATURES.

N0. 492,355. Patented Feb. 21, 1893.

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' L f' f/ l UNTED STATES PATENT OFFICE.

THOMAS H. HICKS, O F DETROIT, MICHIGAN.

MAGNETIC CORE FOR ARIVIATUFIES.y

SPECIFICATION forming part of Letters Patent No. 492,355, dated February21, 1893.

Application le'd October 6, 1892. Serial No. 448,026. (No modeL) To allwhom, it may concern.'

Be it known that I, THOMAS H. HICKS, a subject of the Queen of GreatBritain, residing at Detroit, county of Wayne, State of Michigan, haveinvented a certain new and useful Improvement in aMagnetic CoreforArmatures;

and I declare the following to be a full, clear,

and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, which form a part ofthis specification.

My invention relates to certain new and useful improvements in theconstruction of magnetic cores for armatures, to be used in dynamos andelectric motors, and it consists of the devices and appliances,theirconstruction, combination and arrangement as hereinafter'specied andclaimed,and illustrated in the accompanyingr drawings, in which- Figuresl and 2 are views showing` armatures in section to illustratedetrimental features which my invention is intended to overcome. Fig. 3is an elevation of an armature partly constructed showing the foundationspool of an armature upon a shaft. Fig. .tis a sectional view of thesame on the line Fig. 3, showing the sockets in the collar. Fig. 5 is asimilar section, showing the pins in the collars. Fig. 6 is an elevationof a completed magnetic core, showing yone convolution of wire woundupon the magnetic core.

My object, more especially, is to provide a cheap and eiiicient armatureto take the place of armatures of the well known Siemens type. This typeof armature is usually formed of laminze of sheet iron pressed together,and held in place by large collars having a screw threaded engagementupon the shaft at each end of the armature. When such armatures exceedeight inches in diameter, or thereabout, they usually have bolts runningtherethrough, extending parallel to the shaft, but near the peripheriesof the sheet iron disks, to assist in holding the armature diskstogether. Each sheet iron disk thus requires to have a hole punchedtherein for the armature shaft and also for each of the connectingbolts. This means Not only this,

but moreover, each hole formed in the said disks forms a circuit foreddy currents which I illustrate in Figs. l and 2, and which will beunderstood from thefollowing explanation.

Let A in Fig. I represent a cylindrical metallic armature core rotatablebetween two iield poles N, S, upon the shaft A. It will be found thatthe cylinder will become quite hot, the heat being due to theelectricity generated and short circuited, as indicated by the arrows inFig. 1. In said figure I have shown two arrows in opposite direction onthe shaft A to indicate that the two lines of currents generated inopposite sides of the cylinder would equal and therefore oppose eachother, thus preventing any current from passing through the shaft. Butinstead of using a cylinder, as shown in Fig. l for purposes ofexplanation, if I substitute a solid metallic core, said core upon beingrotated will be found not to manifest any heat, for the reason that thecore being solid it thus forms only on e conductor and consequently noelectricity can be generated. The two magnets N, S would tend to inducecurrents in opposite directions as in Fig. l, but the solid core formingonly one conductor, the two lines of currents would meet as in the shaftof Fig. l. Now, if a hole be bored in any part of the core B, shown inFig. 2, parallel to the shaft A, as indicated for example by the linesat b in Fig. 2, it will be found that that portion of the core next thesaid hole will be warm, due, of course, to locally generated currents.

'When the opening a in the core A is equidistant from the periphery asin Fig. l, the current will be in continuous direction, but when theopening is nearer one side of the core than the other, the currents willalternate in direction as the opening passes each inagnet. The openingdivides the core into two circuits, the opening also forming aninsulation. Bolting an armature together, made of metallic disks, willset up similar currents at each bolt hole. Such detrimental openingswhich are necessary when constructing large laminated armatures I avoidentirely by my present invention, which I will now proceed to describe.

IOO

As shown in Figs. 3,4, 5 and G, myimproved armature core consists of ashaft A provided with a spool A2, said spool formed with a body A3, andwith outstanding collars C, C at the ends thereof.

E denotes a winding of wire, as of iron wire, wound upon the body A3between the collars C, C.

F denotes pins inserted in the collars C, C, which serve to hold theinduction coils in place, which may be connected to either a commutatoror rings in the usual manner. I show one convolution of such inductioncoils at H.

In constructingan armature corein accordance with my present invention,I prefer to cast the. spool A'3 upon the shaft A, using cast iron, onaccount of its cheapness, although the collars C, C may be of separateparts and of distinct material if desired. lVhen the spool A2 is castupon the shaft A in this way, the shaft and spool form one solidintegral body. After the spool is thus east upon the shaft it isproperly turned up in a lathe and then wound with wire E. I prefer touse in winding, rusted iron wire, although unrusted iron wire maybeeinployedif wound upon the iron spool so as to have good metalliccontact therewith. Or iron wire having asuitable covering may be used;but this would make the armature much more expensive and the resultswould not be so good, from the fact that too much valuable inductionspace would be taken up by the covering of the wire. The corrosion ofthe iron wire forms a suitable insulation without other covering, andeconomizes space. The collars C, C are either slotted or drilled asindicated at c to receive the pins F.

It is evident that an armature core cast upon the shaft in this manneris especially adapted for large armatures. The cast iron also serves tostrengthen the shaft, and when properly cast thereupon, the shaft andthe spool become fused together, and any cylindrical opening around theshaft which would divide the cast iron spool into two conductors isthereby entirely prevented.

Of course, the spool A2 could be first cast and then bored to iit theshaft, and I would have it understood that I contemplate such aconstruction as coming within 'the scope of lnyinvention. But such aconstruction would cause extra labor and expense, in boring the spool,turning the shaft and securing the spool upon the shaft. Moreover a muchlarger shaft would be required in the latter case than when the spool iscast upon the shaft. So in various ways my invention is calculated andadapted to secure economy of construction together with superiorefficiency.

Itv will be understood that the amount of wire wound upon the spool willvary with different sized armatures; the minimum depth of the spoolbetween the collars being about half an inch in small armatures, and themaximum being about two and a half inches in large armatures.

. In Fig. 6 is shown one convolution of one conductor bobbin. It will beunderstood that the armature bobbin will be wound in all respectssimilar to the well known Siemens drum armature, each bobbin of saidconductors being wound over the iron wire E parallel with the shaft andcrossing the end of the armature near the shaft, and will therefore needno further description.

Having thus described my invention, what I claim as my invention is- 1.The combination with an armature shaft, of an armature core constructedof cast metal and provided with outstanding collars at its ends, saidcore wound with magnetic wire, substantially as described.

2. The combination with an armature shaft, of an armature core castthereupon and provided with outstanding collars at its ends, said corewound with magnetic wire, substantially as described.

3. The combination with au armature shaft, of an armature coreconstructed of cast metal and provided with outstanding collars at itsends, said core wound with magnetic wire, said collars provided withpins to hold said wire, substantially as described.

4. The combination with an armature shaft, of an armature coreconstructed of cast metal and provided with outstanding collars at itsends, said core wound with magnetic wire, said collars constructed withsockets to receive pins F, substantially as described.

5. The combination with an armature shaft, of an armature coreconstructed of cast metal and provided with outstanding collars at itsends, and a winding of magnetic wire, said core turned up before theapplication of said wire thereupon, substantially as described.

6. The combination with a shaft, of an armature core constructed of castmetal and provided with outstanding collars C C, and' rusted iron wire Ewound upon said core, substantially as described.

In testimony whereof I sign this specification in the presence of twowitnesses.

THOMAS H. HICKS. lVitnesses:

N. S. WRIGHT, J oHN F. MILLER.

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